[milo] Refactor all html knowledge out of backends.

milo/frontend/view_logs.go

Index: milo/frontend/view_logs.go
diff --git a/milo/frontend/view_logs.go b/milo/frontend/view_logs.go
new file mode 100644
index 0000000000000000000000000000000000000000..7f9016893718075b2d797446028610038c692a6d
--- /dev/null
+++ b/milo/frontend/view_logs.go
@@ -0,0 +1,25 @@
+// Copyright 2017 The LUCI Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
+
+package frontend
+
+import (
+	"github.com/luci/luci-go/milo/buildsource"
+	"github.com/luci/luci-go/server/router"
+	"github.com/luci/luci-go/server/templates"
+)
+
+// LogHandler is responsible for taking a universal build ID and rendering the
+// build page (defined in ./appengine/templates/pages/log.html).
+func LogHandler(c *router.Context, buildID buildsource.ID, logname string) {
+	log, closed, err := buildID.GetLog(c.Context, logname)
+	if err != nil {
+		ErrorHandler(c, err)
+	} else {
+		templates.MustRender(c.Context, c.Writer, "pages/log.html", templates.Args{
+			"Log":    log,
+			"Closed": closed,
+		})
+	}
+}